Vehicles such as a hybrid car, a plug-in hybrid car, and an electric automobile are provided with a power driving high voltage battery, an inverter apparatus, a DC-DC converter, and a low voltage battery serving as an auxiliary power source for a low voltage load.
The sizes of the inverter apparatus and the converter are reduced to reduce the ratio of the footprint with respect to the vehicle, so that the inverter apparatus and the converter can be mounted in a small space outside of a cabin. The converter is provided with an inductor device and a capacitor device for smoothing and filtering. The capacitor device is adversely affected by heat emitted by a heating body such as an inductor device, but when the size is reduced, the capacitor device is further more likely to be affected by heat, and therefore, it is an important problem to cope with this issue.
There is a known structure as a conventional electric power conversion apparatus, in which a power semiconductor device, a heat sink, a reactor, and a capacitor, which are in the descending order of heat generation, are arranged in order from the top to be disposed in a stacked manner in a vertical direction and accommodated in a housing. According to this structure, the air heated by the power semiconductor device is less likely to move to around the capacitor arranged at the lower side, and therefore, this structure is considered to improve the reliability (for example, see PTL 1).